Objective: This study aimed to explore the influence of different ultramicro grinding intensity on highland barley powder. Methods: Using ultramicro grinding to prepare different granularity of highland barley powder. Exploring the influence of granularity on the apparent characteristics, nutritional quality. Processing characteristics of highland barley powder. Results: The particle size of highland barley powder gradually decreased with the increase of mesh number. The contents of crude fiber, β-glucan, crude fat and ash of highland barley powder decreased with the decrease of particle size. On the other hand, the crude protein and damaged starch increased with the decrease of particle size. 120 mesh highland barley powder had the highest total mineral content (7 476.05 mg/100 g). Among the barley powder, the color of 140 mesh is the brightest, with L^* value of 86.96. The disintegration value (272.00 mPa·s) and recovery value (151.00 mPa·s) of 60-mesh highland barley powder are the lowest. It has a good shear resistance, anti-aging, and anti-rheological. When particle size decreased, the water holding capacity and oil holding capacity of highland barley powder decreased as well. The solubility went lower and the expansion degree went higher. When the particle size of barley powder decreased, the angle of rest, the angle of slip, the density of packing, the density of vibration, the transmittance of barley powder, and the intensity of X-ray diffraction peak increased. Moreover, 140 mesh highland barley powder had the lowest (47.98%) water extraction rate, therefore, it was the most suitable for processing frozen food. Conclusion: The quality characteristics of young barley powder with different grain sizes are different, so appropriate crushing strength should be selected in the production process.